Well, everyone praises their own swamp. I came up with a random map, and now everyone says duels are pointless. Back in the day, people also criticized the standard format, saying that playing only in the TE standard is boring. Learn how to play, and then criticize. And by the way, I played your map and am participating in the tournament, and there's plenty of imbalance there too (no enchanted items, no mini-artifacts, etc. - imbalance of troops - when two strong players play, the one who gets lucky with items and army will clearly win. You shouldn't compare these two completely different modes!
Regarding the Karl and Shaka pairing, it's quite interesting, and I would also like to play it more. I usually play Shaka defensively (except against mages), but here, maybe
you also need to play offensively.